1. Field of the Invention
The present invention relates to an information processing apparatus utilizing an interface with variable bus band width, and a method and a memory medium therefor.
2. Related Background Art
Among the peripheral equipment of the personal computer, most frequently used are hard disks and printers, and such peripherals are connected and communicate with the personal computer with a general digital interface for small computers, represented by SCSI.
Also recording/reproducing device such as a digital camera or a digital video camera is a peripheral of the personal computer, employed as input means therefor, and there has recently been remarkable progress, with increasing users, in the technology of fetching a still image or a moving image, taken with such digital camera or digital video camera, into the personal computer, then storing such image in the hard disk or editing such image on the personal computer and obtaining a color print of such image with a printer.
In outputting the fetched image data from the personal computer to the printer or the hard disk, the data are communicated without an interface such as SCSI mentioned above, and, for transmitting the information of a large data amount such as the image data, there is required a general-purpose digital interface with a high data transfer rate.
As the digital interface capable of meeting such requirement, the IEEE1394 is recently attracting attention.
However, as the IEEE1394 bus is connected to the personal computer and the peripherals such as the digital camera, the bus band width is assigned not only to the data transmission to the printer but also to the data exchange with other equipment, so that the bus band width or the data transfer amount per unit time is not constant. Consequently the data transfer cannot be realized with a high gradation and a high resolution, and the data transfer with a low gradation and a low resolution results in a printing operation with a low image quality even when a wide bus band width can be secured.
In consideration of the foregoing, the object of the present invention is to provide an information processing apparatus capable of optimum control according to the acquired bus band width, and an information processing method and a memory medium therefor.
The above-mentioned object can be attained, according to the present invention, by an information processing apparatus for generating image data in a generation unit and transmitting the generated image data by synchronous transfer through a transmission unit, the apparatus comprising identification means for identifying the data amount of synchronous transfer, transmittable through the transmission unit at every predetermined time; judgment means for judging whether the image data generated in the generation unit can be transmitted through the transmission unit within the data amount of synchronous transfer identified by the identification means; resetting means for resetting the image quality of the image data to be transmitted through the transmission unit in case the judgment means judges that the image data cannot be transmitted; and control means for causing the generation unit to generate the image data to be transmitted through the transmission unit with the image quality reset by the resetting means.
According to the present invention there is also provided an information processing method for use in an information processing apparatus for generating image data in a generation unit and transmitting the generated image data by synchronous transfer through a transmission unit, the method comprising an identification step of identifying the data amount of synchronous transfer, transmittable through the transmission unit at every predetermined time; a judgment step of judging whether the image data generated in the generation unit can be transmitted through the transmission unit within the data amount of synchronous transfer identified in the identification step; a resetting step of resetting the image quality of the image data to be transmitted through the transmission unit in case the judgment step judges that the image data cannot be transmitted; and a control step of causing the generation unit to generate the image data to be transmitted through the transmission unit with the image quality reset by the resetting step.
According to the present invention there is also provided a memory medium storing a computer readable program for use in an information processing apparatus for generating image data in a generation unit and transmitting the generated image data by synchronous transfer through a transmission unit, the program comprising an identification step of identifying the data amount of synchronous transfer, transmittable through the transmission unit at every predetermined time; a judgment step of judging whether the image data generated in the generation unit can be transmitted through the transmission unit within the data amount of synchronous transfer identified in the identification step; a resetting step of resetting the image quality of the image data to be transmitted through the transmission unit in case the judgment step judges that the image data cannot be transmitted; and a control step of causing the generation unit to generate the image data to be transmitted through the transmission unit with the image quality reset by the resetting step.